Tube-dwelling polychaetes from the Upper Oxfordian of Wapienno/Bielawy, Couiavia region, north-central Poland

Abstract

A relatively rich assemblage of tube-dwelling polychaetes is recognized in the talus facies of the Late Jurassic (Late Oxfordian) biohermal, sponge-cyanobacterial buidup from the Wapienno/Bielawy succession exposed in a salt-dome cored anticline of the Couiavia region, north-central Poland. Fourteen taxa are described belonging to 12 genera: Glomerula Brunnich Nielsen, 1931, sensu Regenhardt, 1961; Cementula Brunnich Nielsen, 1931, sensu Regenhardt, 1961; Ditrupula Brunnich Nielsen, 1931, sensu Howell, 1962; Filogranula Langerhans, 1884; Laqueoserpula Lommerzheim, 1979; Metavermilia Bush, 1904; Mucroserpula Regenhardt, 1961; Neovermilia Day, 1961; Pannoserpula Jager, Kapitzke & Rieter, 2001; Pursimonia Regenhardt, 1961; Placostegus Philippi, 1844; Serpula Linnaeus, 1758. Only very few, or no representatives of these genera have formerly been reported from the Jurassic of Poland. Five species are established as new: Ditrupula meandrica sp.nov., Laqueoserpula intumescens sp.nov., Mucroserpula jaegeri sp.nov., Pannoserpula couiaviana sp.nov., Placostegus conchophilus sp.nov. The ecology of this assemblage, which comprises typically epizoans of sponges, and of brachiopods upon whose shells they often formed 'serpulid gardens', is discussed. In the case of the brachiopods, live specimens were favoured, to which the tube-dwelling polychaetes became commensals located preferably on their ventral valves. Some of the polychaetes had their own commensal, the hydroid Protulophila gestroi Rovereto, 1901, whose stolonal network was embedded in their tubes. The lithology of the source deposits indicates their transport by storm agitation and/or mass movements. Concequently, rapid burial affected all biota, including the living brachiopods, some of which were bearing living polychaetes.